Automatic differential brake-pressure mechanism.



PATBNTED AUG. 23, 1904.

J. LORD.- AUTOMATIC DIFFERENTIAL BRAKE PRESSURE MECHANISM.

APPLIOATION FILED 1330.23, 1903.

no MODEL.

UNITED STATES Patented August 23, 1904. I

PATENT OFFICE.

JOSEPH LORD, OF HAYS, KANSAS, ASSIGNOR OF ONE-HALF TO MARQUIS L.FRIZZELL, OF ST. ANTHONY, IDAHO.

AUTOMATIC DIFFERENTIAL BRAKE-PRESSURE MECHANISM.

' SPECIFICATION forming part of Letters Patent-N0. 768,386, dated August23, 1904.

Application filed December 23, 1903; Serial No. 186,392. (No modeLl Toall whom, it may concern:

Be it known that I, J OSEPH LORD, a citizen i of the United States,residing at Hays city, in

the county of Ellis and State of-Kansas, have invented certain new anduseful Improvements in Automatic Differential Brake Pressure Mechanism,of which the following is a speci- Figure 1 represents a centralvertical section of a differential valve attachment for freight-carauxiliary reservoirs, one of said reservolrs being shown 1n elevationand connected to the differential valve. Fig. 2 is a top plan view ofthe same with the reservoir partly broken away to show wherein itdiffers in construction from those now in general use.

Fig. 3 is a top plan view of the differential valve with its upper heador end omitted. Fig. 4 is a'horizontal section on the'line IV IV ofFig. 1. Fig.5 is a detailperspective view of the valve mechanism. Flg. 6is a central vertical section of the mechanism shown in Fig. 5. Fig. 7is an enlarged horizontal section on the line VII VIII of Fig. 1, saidvalve being arranged to permit the air' topass through it. Fig. 8 is asimilar view with the valve arranged to out 01f such passage of air andto permit of the escape of the air from one side of the piston of thedifferential valve.

In the said drawings, 1 designates theauxiliary reservoir of afreight-car, from which reservoir, however, is omitted the straightpipe, which extends clear through the reservoir and communicates at oneend with the triple valve and at the other with'the brakecylinder. Inthis case I provide in lieu of said pipe a. port 2, which leads to thetriple valve and which I therefore term the triple- Valve port, and aport 8, which leads to the brake-cylinder and which I therefore term thebrake-cylinder port. These ports lead to the outside of thereservoir bypreference,-

and port 2 is connected by a pipe 4 and port the latter toward thevalve-seat partition 9, a

collar 13 or its equivalent serving to limit movement in that direction.

Suspended as shown or otherwise from and movable with the piston is themain valve 1 1, the same being of frustum shape and adapted at certaintimes, as hereinafter explained, to

.iit snugly in the valve-seat opening and close the same. This mainvalveis preferably provided with a depending portion15, having a verticalpassage 16 to receive the depending stem 17 of the supplemental orrelease valve 18, this valve 18 being also by preference of frustumshape and normally held by the weak spring 19 against its seat 20, saidseat being a tapering passage formed entirely through the main valve.

I 21 designates a system of pipes communicatingwith the cylinder throughits closed ends or heads, as shown most clearly in Fig. 1, and providedat a suitable point with a plug-valve 22, said plug-valve having theusual passage 23 to establish communication between opposite ends of thecylinder when disposed as shown'in Fig. 7 It is also provided with alongitudinal groove 24:, which has one end communicating with theatmosphere and its opposite end when the valve is. in the position shownin Fig. 8 commumcating with that end of the cylinder 8 at the oppositeside of the piston from the main and supplemental valves. valve carriesa cross-rod 25 at its upper end, and connected to opposite ends of thesame and extending to within convenient reach from opposite sides of thecar are pull-rods 26 and 27. The plug-valve has only sufficient movementto swing the passage 23 out of and groove 24: into alinement with pipe21, or vice versa, its movement being limited by preference by the usualpin-and-slot connection 28, commonly used on valves of the type underconsideration.

In practice the brakeman of the train will by proper manipulation of thepull-rods set the plug-valves on all of the empty cars, as shown in Fig.8, so that air cannot pass through the plug-valves to the cylinder, butcan escape from the latter through the groove to atmosphere. On theloaded cars the plug-valves will be set as shown in Fig. 7that is, sothat the air can pass freely from one end of the cylinder to the otherand in this connection it should be stated that the brakeman will knowby the position of the pull-rods how the plug-Valves are setthat is tosay, if the pullrod handles (not shown) are close to the edges of thecar he will know that the plug-valves are disposed as shown in Fig. 8and that the valve is set for empty cars. If the handles are somedistance back from the edge of the cars, he will know that theplug-valves are set as shown in Fig. 7 for loaded cars.

Assuming that the engineer has made an emergency application of thebrakes on a train composed of loaded and empty cars equipped withdifferential valves embodying my invention, it will be seen that the airfrom each pipe 4 enters chamber 6 of the cylinder and from said chamberpasses up through the mainvalve seat into chamber 7 and through pipe 5to the brake-cylinder. On each loaded ear, because the plug-valve is setopen, the air immediately passes through pipe 21 to the cylinder at theopposite side of the piston, and as a result the latter is balanced andthe main valve is held unseated, and therefore does not interfere withthe application of full pressure in the brake-cylinder. On each emptycar as the plug valve occupies its closed position the air cannot passthrough pipe 21 to the opposite side of the piston, and as a result assoon as the pressure of air entering chamber '7 from chamber 6 reachesfrom twenty to thirty pounds it overcomes the resistance of spring 12and forces piston 10 to move and seat the main valve, so as to cutoffthe passage of additional airfrom chamber 6 to chamber 7, and thusprevent the application of more than the twenty or thirty poundspressure referred to in the brake-cylinder of the empty car, the

The stem of the plug- I surplus air above the piston being forcedthrough the groove 24: to atmosphere by such movement of the piston.

it is to be understood, of course, that the amount of resistance whichspring 1). exerts will correspond to about the maximum pres sure whichshould be applied in the brakeeylinder of an emptycar. As a result,adifferential pressure is automatically applied on loaded and empty carsof the same train, and the flattening of the wheels of the latter isavoided.

To effect a quick release of the brakes, the main valve is provided withthe small supplemental or release valve, which is held s ated by theweak springll) only when the pressure from the auxiliary reservoir isremoved. As a consequence the instant the engineer exhausts the airthrough pipe 4 the back pressure in chamber 7 between the piston and thebrakecylinder unseats said release-valve and effects the preliminary orimmediate release of the brakes, the unseating of the main valveimmediately following. The main valve would not drop quickly enough togive ei'licien t service, beeause the back pressure from thebrakecylinder on the larger area of the piston would tend to hold it,and therefore said valve, up until the pressure was lowered by leakagefrom the brake-cylinder, as will be readily understood. Moistureaccumulating in the differential-wtlve casing will be discharged by wayof the drain-cock 29.

From the above description it will be apparent that I have produced adifferential valve for automatically applying differential pressure onloaded and empty cars of the same train which operates eiliciently,positively, and reliably and which can be applied to cars at acomparatively low cost, and whilel have illustratedand described thepreferred embodiment of the invention it is to be understood that it issusceptible of modification in various particulars without depa rtingfrom its principle and scope or sacrificing any of its advantages.

Having thus described the invention, what I claim as new, and desire tosoon re by Letters Patent, is

l. The combination of a casing having sup ply and discharge ports, andvalvemechanism yieldingly controlling thepassage of air from one port tothe other, a piston movable with said valve mechanism and disposed atthe opposite side of the discharge-port from the valve mechanism, a pipeconnecting the casing at opposite sides of the piston, a valve mountedin said pipe and provided with a passage, and with a groove, the latterconnmmicating at one end with atmosphere and adapted to communicate atits other end with that portion of the pipe leading to the end of thecylinder at the opposite side of the piston from the valve mechanismthereof.

2. The combination with a casing having supply and discharge ports, andvalve mechanism yieldingly controlling the passage of air from one portto the other, a piston movable with said valve mechanism and disposed,at the opposite side of the discharge-port from the valve mechanism, apipe connecting the easing at opposite side of the piston, a valvemounted in said pipeand provided with a passage, and with a groove thelatter communicating at one end with atmosphere and adapted tocommunicate at its other end with that por' tion of the pipe leading tothe end of the cylinderat the oppositeside of the piston from the valvemechanism thereof, and pull-rods for controlling the valve of said pipe.

3. The combination of acasing having supply and discharge ports, a valvemechanism between said ports, means adapted to be actuated by the airfrom the supply-port to close the valve mechanism, and means actuated bythe back pressure from the discharge-port.

ply and discharge ports, a valve mechanism between said ports, means forholding the valve mechanism seated, and means actuated by the backpressure through the dischargeport when the pressure at the oppositeside of the valve mechanism is removed to efiect a.

preliminary reduction of pressure through the discharge-port.

6. The combination of a casing having su pply and discharge ports, avalve mechanism between said ports, means for holding the valvemechanism seated, means actuated by the back pressure through thedischarge-port when'the pressure at the opposite side of the valvemechanism is removed, to eifect a pre liminary reduction of pressurethrough the discharge port, and means to immediately thereafter unseatsaid valve mechanism.

7. The combination of a casing having supply'and discharge ports, avalve mechanism between said ports and heldnormally unseated, a pistonat theopposite side of the discharge-port from the valve mechanism, and

connected to the latter, a spring holding the valve mechanism normallyopen, a pipe communicating with the casing at opposite sides of thepiston and valve mechanism, and means for opening communication throughsaid pipe to the casing, or for shutting off such 'communication. andopening communication between the atmosphere andthe end of the easing atthe opposite side of the piston from the discharge-port.

8. The combination of an auxiliary reservoir having a triple-valve port,and a brakecylinder port, a casing having a supply-port connectedto thetriple-valve port of the res-- ervoir and a discharge-port connected tothe brake-cylinder port of the reservoir, a valve mechanism between saidcasing-ports and held normally unseated, a piston at the opposite.

side of the discharge-port from the valve mechanism, and connected tothe latter, a spring. holding the valve mechanismnorrnally open, a pipecommunicatingwith the casing at opposite sides of the piston and valvemechanism, and means for opening communication through said pipe to thecasing or forshutting off such communication and opening communicationbetween the atmosphere and the'end of the casing at the opposite side-ofthe piston from the discharge port.

In testimony whereof I afiix my signature in the presence of twowitnesses.

JOSEPH LORD.

Witnesses:

H. (1. RODGERS, G. Y. THORPE.

